Liver Function Test (LFT)

Liver Function Test (LFT) – Details & Precautions

The Liver Function Test (LFT) is a blood test used to evaluate liver health by measuring different enzymes, proteins, and substances in the blood. It helps diagnose liver diseases, infections, liver damage, and monitor ongoing treatments.

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Details of the LFT Test

Purpose

• Diagnoses liver diseases such as hepatitis, fatty liver disease, cirrhosis, and liver infections.
• Monitors liver damage due to alcohol, medications, or toxins.
• Evaluates jaundice (yellowing of skin/eyes).
• Assesses liver function in patients with chronic liver disease.
• Helps track the effects of medications or treatments affecting the liver.

Test Components

• Alanine Aminotransferase (ALT) – Detects liver cell damage.
• Aspartate Aminotransferase (AST) – Measures liver and muscle enzyme levels.
• Alkaline Phosphatase (ALP) – Assesses bile duct function.
• Bilirubin (Total & Direct) – Measures waste product from red blood cells, used to diagnose jaundice.
• Albumin & Total Protein – Checks liver’s ability to produce proteins.
• Gamma-Glutamyl Transferase (GGT) – Detects bile duct and alcohol-related liver damage.
• Prothrombin Time (PT/INR) – Measures blood clotting ability, which is affected by liver function.

Test Method

• A blood sample is drawn from a vein in the arm and analyzed in a laboratory.

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Precautions for the LFT Test

Before the Test

✅ Fasting:

• Fast for 8–12 hours before the test (only water is allowed).
• Some LFT components, like bilirubin and enzymes, are affected by food.

✅ Hydration:

• Drink plenty of water to make blood collection easier.

✅ Medication Restrictions:

• Inform your doctor about any medications, especially antibiotics, painkillers, statins, and steroids, as they can affect results.
• Avoid over-the-counter painkillers (NSAIDs like ibuprofen) and herbal supplements before the test.

✅ Avoid Alcohol & Smoking:

• Avoid alcohol for at least 24–48 hours before the test, as it can increase liver enzyme levels.

✅ Avoid Heavy Fatty Meals:

• Do not eat oily or high-fat foods before the test, as they can affect triglycerides and liver enzyme levels.

✅ Avoid Strenuous Exercise:

• Intense workouts can temporarily increase liver enzyme levels.

During the Test

• A small blood sample is taken from a vein; mild pain or bruising may occur at the injection site.

After the Test

✅ Resume normal activities immediately.
✅ If fasting, eat a balanced meal after the test.
✅ Drink plenty of water to stay hydrated.